Abstract 9396: Derivation of a Clinical Algorithm Based on Cardiopulmonary Exercise Tests in Patients With Heart Failure
Introduction: Cardiopulmonary exercise testing (CPX) is used to assess prognosis in patients with heart failure (HF). Clinical algorithms have been suggested to identify risk but many algorithms offer little assistance in identifying patients who may benefit the most from advanced therapies (cardiac transplantation and left ventricular assist device (LVAD) implantation) and identifying a proper sized cohort who have a reasonable expectation to achieve advanced therapies.
Hypothesis: We assessed the hypothesis that CPX would help identify a very high risk cohort, corresponding to the sickest 10 percent of the population, who had a reasonable expectation to require and achieve cardiac transplantation.
Methods: HF patients (n=399, 51±10 years) underwent CPX and had event follow-up (mortality and cardiac transplantation) for 10 years.
Results: The Cox Regression model that best identified survival included only VE/VCO2 slope (37.7±10.7 ,Wald=25.1) and SBP≤100mm Hg (Wald=20.1) and not peak VO2 (16.3±4.9 ml·kg·min-1,Wald=4.5). SBP increased the risk associated with VE/VCO2 slope quartiles; a lower VE/VCO2 slope quartile with a low SBP was associated with a greater risk of mortality than the next greater VE/VCO2 slope quartile with a higher SBP (>100 mm Hg). The figure shows that low SBP combined with the highest quartile of VE/VCO2 slope (>41) identified a very high risk cohort representing 9% of the population that had 65% 2-year event rate; low, intermediate, and high risk groups had 5%, 16%, and 30% 2-year event rates, respectively. Unlike SBP, a low peak VO2 did not affect the predictive ability of VE/VCO2 slope.
Conclusions: The combination of VE/VCO2 slope and SBP provided a simple, robust means of identifying a wide spectrum of risk. The combination of a high VE/VCO2 slope >41 and a low SBP ≤ 100 mm Hg identified patients with a very high risk of mortality with a reasonable expectation of undergoing advanced therapies .
- © 2010 by American Heart Association, Inc.